Childhood-onset
systemic lupus erythematosus (cSLE) exhibits an aggressive clinical
phenotype and severe
complications. This could be due to a pro-inflammatory
cytokine milieu. Therefore, we determined
plasma levels of Th1 (
IL-2, IFN-γ, TNF), Th2 (
IL-4), Th17 (
IL-17A,
IL-6), and Treg (
IL-10)
cytokines in a cohort of cSLE
patients and healthy controls, and we evaluated the
association between these
cytokines and
disease activity. We conducted a
cross-sectional study with 51 cSLE
patients from two pediatric
rheumatology services. Ten cSLE
patients participated in a longitudinal
follow-up study.
Blood samples were collected from the same
patient during active and inactive
disease.
Disease activity was evaluated according to SLE
Disease Activity Index 2000 (SLEDAI-2K).
Cytokines levels were measured by cytometric bead array
technique. cSLE
patients had higher
IL-6 (P<0.001) and
IL-10 (P<0.001) levels than healthy controls.
Patients with active
disease had higher
IL-6 and
IL-10 levels than
patients with inactive
disease (P=0.001 and P=0.014, respectively) and the
control group (both P<0.001).
IL-6 (P=0.022),
IL-10 (P=0.013), and
IL-17A (P=0.041) levels were significantly higher during active than inactive
disease.
Linear regression analysis revealed
IL-6 (P=0.002, 95%CI=0.006-0.025) and
IL-10 (P=0.01 95%CI=0.021-0.150) as independent factors for increased SLEDAI-2K.
IL-6,
IL-10, and
IL-17A are candidate
biomarkers for
disease activity in cSLE
patients. This is the first
longitudinal study to support their pivotal
role in the
pathogenesis of the
disease.